1. Field of the Invention
This invention relates to a method for forming alkyl silicate in a single step.
2. Description of the Related Art
Metallic silicon has been used as high-functional materials for solar cells, semiconductors, etc. in view of its physical and chemical properties. The metallic silicon has to have a single crystal body in order to exhibit a higher function. For this reason, researches have been conducted on growth of single silicon crystal actively and extensively since 1950's, and some methods of producing crystals have been reported. Among them, the most general and most economic method is Czochralski process which was developed in 1918. However, Today's general method of synthesizing high-purity metallic silicon is to use easily available silicon dioxide as a raw material, mix silicon dioxide with a carbon reducing agent, heat the mixture above 2000.degree. C., and continuously supply an electric power of 13 MK.sup.wh /t.
However, silicon dioxide used as a raw material is synthesized from silicon tetrachloride or alkoxy silane. Alkoxy silane is synthesized from silicon tetrachloride, and silicon tetrachloride is synthesized from crude metallic silicon.
Due to these complicated synthesizing processes, high-purity metallic silicon is very expensive. So, the present inventors have studied about a method of obtaining inexpensive alkoxy silane by using cheap water glass as a raw material.
As for organic derivatives of water glass, few researches have been made since Eblemen produced an organic silicon compound in 1844. One of the few reports is that Kird made direct esterification of polymerized silicon in 1946, and another is that in 1947, Iler et al synthesized polyester silicate in a two-step reaction in which water glass was first treated by acid and then the resultant was reacted with alcohol.